Year Percent 1980-01-01 1.6402599999999998 1981-01-01 1.4950200000000000 1982-01-01 1.4756500000000000 1983-01-01 2.1726799999999997 1984-01-01 2.2461700000000000 1985-01-01 8.6693000000000000 1986-01-01 14.8020000000000000 1987-01-01 17.8714000000000000 1988-01-01 19.2180000000000000 1989-01-01 25.8059000000000000 1990-01-01 31.9993000000000000 1991-01-01 31.5466000000000000 1992-01-01 35.2198000000000000 1993-01-01 50.6833000000000000 1994-01-01 51.8741000000000000 1995-01-01 48.2312000000000000 1996-01-01 45.5556000000000000 1997-01-01 41.6854000000000000 1998-01-01 52.3022000000000000 1999-01-01 59.9750000000000000 2000-01-01 78.9704000000000000 2001-01-01 100.1500000000000000 2002-01-01 105.3639999999999900 2003-01-01 132.1910000000000000 2004-01-01 195.1770000000000200 2005-01-01 243.7750000000000000 2006-01-01 316.2920000000000300 2007-01-01 293.7770000000000000 2008-01-01 294.1280000000000000 2009-01-01 367.1930000000000400 2010-01-01 291.8780000000000000 2011-01-01 212.3730000000000000 2012-01-01 146.5600000000000000 2013-01-01 109.8789999999999900 2014-01-01 88.7441000000000000 2015-01-01 75.7787000000000000 2016-01-01 55.7572000000000000